They take public domain footage, mostly us government stuff, and release it and claim copyright over it.
I took some of their public domain footage and put it on YouTube and they freaked out.
Through logic and reason I was able to get them to admit they have no copyright right, as they were initially claiming.
But they did have the YouTube terms of service.
So, back to this.
If they had public domain stuff they wanted to protect, this is another less obvious way to do it.